【作者】 郑翔翔；

【导师】 周立祥；

【作者基本信息】 南京农业大学 ， 环境工程， 2007， 硕士

【摘要】 城市污泥是城市污水处理厂不可避免的产物。随着工业的发展和城市化进程的加快，城市污泥的产量急剧增加。城市污泥中含有丰富的有机质及氮、磷等营养元素，但同时也含有种类较多含量不等的重金属、微量的有机污染物和病原物，必须对其进行妥善处置。目前，国内外主要的污泥处置方法有填埋、焚烧和土地利用等。由于不同地区经济技术水平、土地资源、污泥泥质与产生量、相关产业的发展期模与程度等均存在很大差异，各地区应遵循因地制宜的原则，根据自身特点选择适合本地区的污泥处置方式。本文将研究内容分为三大部分：一是江苏省城市污泥产量和处置现状调查，采用问卷调查和实地调研相结合的方式进行；二是江苏省城市污泥泥质调查，对城市污泥中热值、有机质及养分含量、重金属含量进行了研究分析；三是在研究城市污泥处置现状和污泥泥质的基础上，提出了几种污泥处置方式的技术规范，并对江苏省城市污泥管理政策的制定提出了一些建议。根据调查结果估算，目前江苏省城市污泥产生量(以干物质计)约15万吨／年，产生的城市污泥大部分采用填埋方式处置，即污泥脱水后，雇佣车辆拉至远近不等的垃圾填埋场与垃圾混合填埋。但是随着人口的增加，土地资源匮乏，可供填埋的场地已十分有限，加上许多垃圾填埋场开始拒绝接收污泥，全省特别是苏南地区污泥大量产生而无出路的矛盾已显得十分尖锐。对江苏省城市污泥热值、有机质及养分含量分析表明：江苏省不同地区城市污泥热值的大小有较大的差异，苏锡常地区城市污泥的热值较高，在10000～15000kJ／kg之间，而苏北地区城市污泥热值普遍在10000kJ／kg以下。江苏省城市污泥的有机质、全氮、全磷和全钾含量平均值分别为404g／kg、36.0g／kg、16.1g／kg和3.7g／kg，除了全钾外均高于一般厩肥。对江苏省城市污泥重金属含量分析表明，江苏省城市污泥中重(类)金属元素平均含量的大小顺序为Zn＞Cu＞Cr＞Ni＞Pb＞Cd＞As＞Hg，80％统计样本的Pb含量在120 mg／kg以内，而Cd、Cr、Ni、Cu和Zn含量则分别在8.50、411、140、1410和1650mg／kg以内。Hg和As含量较低，平均值分别为2.75和5.86 mg／kg。苏南地区城市污泥中重金属含量普遍高于苏中和苏北地区。连续提取方法对重金属分级表明，江苏省城市污泥Cd主要分布在残余态，Cu和Cr主要以可氧化态和残余态形式存在，Ni和Zn的残余态含量较低而酸可提取态较高。按照我国《城镇污水处理厂污染物排放标准》(GB18918-2002)规定的污泥农用标准(在中性和碱性土壤上)，除Pb、As和Hg外，重金属元素Cd、Cr、Ni、Cu、Zn均有超标现象，其中Cu是超标率最高的重金属，超标率为18.6％。苏南地区重金属超标率高于苏中和苏北地区，其中少数几个城市污水处理厂部分重金属超标较严重。经危险废物特征鉴别，3个城市污水处理厂的污泥属于危险废物范畴。目前，江苏省城市污泥处理处置中存在许多问题，应从技术层面和管理层面两方面进行解决。建议在城市污水处理厂密集的苏锡常地区，实现污泥集中处置方案，特别是重点发展(污泥干化后)焚烧或填埋处置方案；南京、镇江及苏中地区重点发展污泥高干度脱水后单独填埋处置或混合填埋技术；污水处理厂密度小的苏北地区重点发展填埋技术以及土地利用方式处置技术。建议在原水价基础上新增水价0.14～0.20元／m~3，作为污泥处理处置费收取，按经济发展水平，苏南地区取上限，苏北地区取下限，其他地区为中等偏上。更多还原

【Abstract】 Municipal sludge is an inevitable byproduct from wastewater treatment plants. With the development of industry and the rapid process of urbanization, there is a dramatic increase in production of sewage sludge. There are lots of soil nutrients such as nitrogen, phosphorus and organic matter contained in municipal sludge. However, there are also heavy metals, organic pollutant and pathogenic bacteria in sludge. So the municipal sludge should be treated and disposed properly. Sludge disposal technologies include incineration, landfill, land application, etc.It is significant to choose the effective technology to dispose municipal sludge according to the actual condition of different area.There are three parts in this text. In the first part, the present situation of production, performance and disposal of sludge were introduced based on the detailed research of the wastewater treatment plants in Jiangsu Province. In the second part, the contents of organic matter, nutrients, heavy metals and heat in sewage sludge of Jiangsu Province were detected. In the third part, technology and management policies about disposal of municipal sludge were researched.The investigation on sludge production showed that wastewater treatment plants in Jiangsu Province pruduced 150000 ton sludge annual. Most of wastewater treatment plants in Jiangsu Province adopted landfill to dispose sludge. However, with the development of population, there is less land that can be used as landfill ground. What is more, the municipal sludge were refused to go to landfill ground. So the problem on disposal of municipal sludge in Jiangsu Province especially in southern Jiangsu is becoming more and more serious.The investigation on sludge character showed that the heat in municipal sludge in southern Jiangsu were higher than that in northern Jiangsu. The heat in sewage sludges of Suzhou, Wuxi and Changzhou city were between 10000-15000 kJ/kg, but the heat in sewage sludges of northern Jiangsu were under 10000kJ/kg. The average contents of organic matter, total N, total P and total K were 404, 36.0, 16.1 and 3.7g/kg respectively, which were all higher than their responding contents in stall manure, except for total K.The average contents of heavy metals in sewage sludge exhibited an order of Zn>Cu >Cr>Ni>Pb>Cd>As>Hg. The concentrations of heavy metals in 80% of sewage sludge samples were found to be lower than 120 mg/kg for Pb, 8.5 mg/kg for Cd, 411mg/kg for Cr, 140 mg/kg for Ni, 1410 mg/kg for Cu, 1650 mg/kg for Zn. The average concentrations of Hg and As were 2.75 and 5.86 mg/kg. As a whole, the heavy metal concentrations in sewage sludge in southern Jiangsu were higher than that in central part and northern part. The fractions obtained by the sequential extraction procedure indicated that Cd were dominantly associated with residual fraction. Cu and Cr were principally distributed in the oxidizable fraction and residual fraction. For Ni and Zn, the concentrations of the acid extractable metals were high, indicating their relatively high bioavailability.Except for Pb, Hg and As, the concentrations of Cd, Cr, Ni, Cu and Zn in several wastewater treatment plants exceeded the heavy metal limits of sewage sludge for land application in China and Cu was the most primary heavy metal pollutant in sewage sludge in Jiangsu Province. Most municipal sludge samples which exceeded the heavy metal limits for land application were in southern Jiangsu. The concentrations of some heavy metals in the municipal sludge of southern Jiangsu exceeded the heavy metal limits severely. Among them, three municipal sludge samples were identified as hazardous wastes.At present, there existed a lot of problems on disposal of municipal sludge. The problem should be solved from the aspect of technology and management. The sludge in Suzhou, Wuxi and Changzhou city were suggested to be disposed together and the best way to dispose them should be incineration or landfill after dried processing. We suggested that the best way to dispose sludge in Nanjing, Zhenjiang and central Jiangsu was landfill and it could be landfilled solely or with municipal solid waste. We also suggested that 0.14-0.20 yuan/m~3 should be added to the present water fee as the charge of municipal sludge disposal.更多还原